A Comparative Study On The Biological Characters Of The Inbred And Hybrid First Generation Between Siniperca Chautsi And S.scherzeri Those Came From Different Regions

Mandarin fish(Siniperca)is an important and precious freshwater fish in China,which is deeply favored by consumers.The common aquaculture breed of mandarin fish(Siniperca)are Siniperca chuatsi and S.scherzeri.However,it is worth noting that there are different culture breeding characteristics between Siniperca chuatsi and S.scherzeri.In contrast to S.scherzeri,S.chuatsi only intakes live bait and is vulnerable to disease,but S.chuatsi has the faster growth rate and larger farm scale compared with S.scherzeri.Meanwhile,these differences imply Siniperca chuatsi and S.scherzeri are remarkable complementary to each other.Therefore,using cross-breeding to concentrate the advantages of S.chuatsi and S.scherzeri can become an positive and effective means for the continuous development of mandarin fish.The comparative study on the biological character,including morphological characteristics anti-oxidative,index non-specific immune index,digestive enzyme,consumption rate and suffocation point,of F1 of the self-crossbred of S.chuatsi in Guangdong,F1 of the self-crossbred of S.scherzeri in Liaoning,S.chuatsi ? and S.scherzeri? F1 and S.scherzeri ? and S.chuatsi ? F1 was carried out with the purposes to understand the performance of genetic traits of offspring,and the differences of the traits of the two hybrids to provide reference for the crossbreeding of mandarin fish.1.Morphological feature comparisonThe shape and distribution of the body spots of the hybrid offspring was similar,and closer to S.scherzeri.S.chuatsi ? and S.scherzeri ? F1 had more than one dark brown band passing vertically down the lateral line from the dorsal fin than S.scherzeri ? and S.chuatsi? F1.There were significant differences among the amounts of dorsal fin(D),pectoral fin(P),tail fin(T)of F1 of the self-crossbred of S.chuatsi in Guangdong,F1 of the self-crossbred of S.scherzeri in Liaoning,S.chuatsi ? and S.scherzeri ? F1 and S.scherzeri ? and S.chuatsi? F1(P<0.05),and the countable comprehensive hybrid index of the orthogonal F1 generation was closer to female parent,while the countable comprehensive hybrid index of the anti-cross F1 generation belongs to the intermediate type.Except the hepatosomatic index,there were significant differences between the ratios of the quantitative traits of the four groups(P<0.05).The average hybridization coefficient of the hybridized offspring was closer to female parent.Clustering analysis results show that the closest form between S.chuatsi ? and S.scherzeri ? F1 and S.scherzeri ? was closest.Through discriminant analysis,this study selected eight ratio traits which contribute a large amount and built shape discriminant,and discriminant accuracy rate is,respectively,95.24%,81.58%,77.78% and 84.72%,and the comprehensive discriminant accuracy rate is 84.83%,which can better distinguish four groups2.The comparison of antioxidant and immune indicatorsS.scherzeri had the higher activities of CAT,SOD,ACP,AKP than S.chuatsi,and The anti-oxidation and non-specific immune index values of the hybrid generation are basically between those of S.chuatsi and S.scherzeri.However,the activities of CAT,SOD,T-AOC of several issues of the hybrid generation were higher than the parents,which indicated the hybrid generation had superior immunodominance.In addition,34.91±7.19 U/mL of the activity of ACP and 7.27±0.42 U/m L of the activity of AKP of serum of orthogonal F1 generation were significantly higher than those of F1 generation of reciprocal cross(P<0.05).3.The comparison of activities of digestive enzymeThe protease activities of pylorus of the self-crossbred of S.chuatsi in Guangdong,F1 of the self-crossbred of S.scherzeri in Liaoning,S.chuatsi ? and S.scherzeri ? F1 and S.scherzeri ? and S.chuatsi ? F1 were strongest in the digestive tract,and the differences among different species were small.The differences of protease activity in the digestive tract were: pylorus> foregut> midgut >stomach >hindgut.The protease activity of the hybrid offspring was slightly higher than that of the self-crossbred offspring,and 21.63±1.61U/mgprot of the protease activity of stomach of orthogonal F1 generation were significantly higher than 19.44±1.12 U/mgprot of that of F1 generation of reciprocal cross(P<0.05).The activity of lipase in the digestive tract was similar to protease,with the highest activity of pylorus in the pylorus,and the activity of lipase of the hybrid generation was significantly greater than that of the self-crossbred group(P<0.05),and there were no significant differences between the hybrid generation(P>0.05).The activity of amylase was the highest in the stomach,and was the weakest in the pylorus,but there were no significant differences in the other parts of digestive tract(P>0.05).Menwhile,the activity of amylase of the self-crossbred groupwas significantly higher than that of the hybrid generation(P<0.05).In addition,1.14±0.19 U/mgprot of the activity of amylase of stomach of orthogonal F1 generation were significantly higher than 0.69±0.08U/mgprot of that of F1 generation of reciprocal cross.4.Study on oxygen consumption rate and suffocation pointThe oxygen consumption rate of mandarin fish was inversely related to individual size,and the oxygen consumption rate of Siniperca chuatsi was higher than S.scherzeri.Moreover,the highest rate of oxygen consumption appeared in the seedlings,and the lowest rate appear in the two ages.The oxygen consumption rate of the hybrid offspring was significantly higher than that of the self-crossbred offspring(P<0.05),and 0.44±0.26 mg/g·L of the oxygen consumption rate of the seedlings of orthogonal F1 generation was highest among the groups.The suffocation point of the hybrid offspring was significantly lower than that of the self-crossbred offspring(P<0.05),and 0.61±0.08 mg/g·L of the suffocation point of the seedlings of orthogonal F1 generation was lowest among the groups.In addition,the suffocation point of S.scherzeri was significantly higher than that of S.chuatsi(P<0.05),and1.55±0.11 mg/L of the suffocation point of the seedlings of S.scherzeri was highest.The diurnal variation of the oxygen consumption rate of experimental fish were characterized by higher level at noon(10~12)and lowest level at midnight.According to the above comparison,the demand for non-specific immunity and dissolved oxygen in the progeny is superior to that of the other three kinds of mandarin fish.